Trading, Market Microstructure and Market Operations
Market structure
The MSE operates an order-driven market with broker intermediation, trading sessions, order types and price-time priority. The exam tests how orders execute, how the rulebook handles auctions and halts, and how market operations support fair and orderly trading.
Core concepts
- Limit orders set a maximum buy price or minimum sell price; market orders execute against available liquidity and can walk the book.
- Price-time priority generally ranks better price first and, at the same price, earlier time first.
- Board lots, tick sizes and any price limits or circuit breakers are rulebook parameters.
- Brokers owe order-handling, best-execution, record-keeping and client-priority duties; market surveillance looks for manipulation, spoofing and wash trades.
Worked example
Order book: bids 100.00 for 500 shares and 99.50 for 1,000; asks 100.50 for 300 and 101.00 for 800. A market buy for 600 shares fills 300 at 100.50 and 300 at 101.00, average 100.75. A limit buy at 100.00 does not fill because the best ask is 100.50. The reasoning is simple: market orders take liquidity at successive asks; limit orders wait unless marketable.
Traps
- Assuming a market order guarantees the quoted price.
- Confusing a board lot with a round lot or ignoring odd-lot rules.
- Forgetting to adjust orders for splits, dividends or rights issues.
- Treating “best execution” as a single best price rather than best overall terms.
- Missing that client orders generally precede principal orders.